Caps and footprints align with IEC 60061 so fixtures and trims stay interchangeable: E27/E14 screw, GU10/GZ10 for mains spots, G13/G5 for linear, GX53/G53 for shallow fixtures, and GU5.3 for MR16. Bodies ship in thermoplastic for general duty or ceramic where shade temperatures run high. Holder classes are typically T180 (polymer) and T210–T300 (ceramic). Contacts use nickel-plated brass or phosphor bronze; terminations accept 0.5…2.5 mm² Cu with screw-clamp or push-in cages. Lead insulation is 90–110 °C as standard. Front IP is defined by the luminaire; the holder itself remains IP20. Safety references: IEC/EN 60598-1 for assemblies, IEC 60432-1/-2 for lamp safety where relevant.
Thermoplastic cups (PA/PC blends, glow-wire 650–850 °C) keep weight and cost down in ceiling voids; ceramic collars and cups ride higher envelope temperatures in enclosed shades, downlights over cooklines, and compact heritage trims. Threaded collars on E-caps resist torque during relamping; GU10 cups are fire-hood friendly with spring retainers and rear strain-relief bosses. Tombstones for G13 are available in locking variants to prevent tube twist on maintenance. For linear retrofits, short-body G5 seats maintain creepage around metal gear-trays in slim channels.
Crossbars, clamp rings, spring carriers, and gear-tray plates share hole geometry across diameters (Ø68/Ø75/Ø83/Ø100/Ø120 mm) so downlight cut-outs stay standardized. Retaining springs are tempered steel with anti-buzz pads for open ceilings; heavy trims add double-spring carriers. For linear luminaires, snap-in rails position G13/G5 tombstones at fixed pitch; R7s cradles include ceramic spacers and screw-through feet. Ceiling roses pair with cord-grip inserts and captive strain-relief to keep pendant loads within pull-out spec (≥60 N typical).
Service drawers mirror wear items: lamp-side collars, anti-twist rings, replacement springs, cord-grips, threaded lock-nuts, gasket sets, and heat shields. Kit codes bundle holder + bracket + fixings so a single line closes a node on the BOM. For bathrooms or wash-adjacent rings, front-seal kits and IP gaskets are available to complete the luminaire’s IP44/IP54 face. Label sleeves and QR tags keep holder type and T-class visible during inspections.
For pendant sets, specify cap + rose + strain-relief as one pick; spl lighting bulb sockets in public zones should be paired with vandal-resistant canopies. In data-adjacent ceilings, keep SELV circuits separated and route control next to shield-friendly glands; panel builders often add spl lighting lighting connectors with keyed polarity on driver leads to avoid mix-ups during service. When schedules group holders with brackets and roses under spl lighting electrical lamp fittings, match finish (white/black/aluminium/bronze) across the page so visible hardware reads as one system.
Standards snapshot (for submittals)
IEC/EN 60598-1 (luminaires), IEC 60061 (caps/bases), IEC 60432-2 (tungsten-halogen holders), EN 62444 (glands/strain-relief), IEC 60695-2-11/-12 (glow-wire for plastics).
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